1. Field of the Invention
The invention relates to a Coriolis mass flow meter having at least one curved measuring tube, at least one oscillation generator, at least one oscillation sensor, at least one measuring device electronics and a housing.
2. Description of Related Art
Coriolis mass flowmeters are known in the prior art in a variety of configurations. Mass flowmeters that operate according to the Coriolis principle usually have at least one oscillation generator, which excites the measuring tubes to oscillation as well as, often, two oscillation sensors with which the achieved oscillation or achieved oscillations of the measuring tubes are detected. The oscillation sensors are commonly fixed on the inlet and outlet sides of the measuring tubes. Without flow, the signals of the two oscillation sensors are essentially in-phase. With a mass flow, a different Coriolis force results on the inlet and outlet sides, which leads to a phase shift of the two signals of the oscillation sensor, wherein the phase shift is proportional to the mass flow rate within the measuring tube.
The oscillation generator and the oscillation sensor are usually constructed such that, for example, they have a permanent magnet and a magnet coil, in order to transmit oscillations by electrical means onto the measuring tubes or to detect oscillations of the measuring tubes.
Coriolis mass flowmeters having curved flow tubes, and having a housing that surrounds the measuring tube, are known. Such housings are, for example, formed as a sheet metal component with a separate supporting structure—often referred to as bridge—, on which the flow tubes are supported. To prevent damage to the housing from medium unintentionally escaping from the measuring tube, for example, via a leak, such housings, for example, have a pressure relief valve that reduces the pressure in the housing at a certain threshold value, thereby preventing damage to the housing. Such solutions are not suitable for use in which, for example, the escape of the measuring medium into the surroundings is to be prevented in all cases, and this applies, for example, to use in power stations.
Coriolis mass flowmeters known from the prior art have the disadvantage that it is possible for deformation of the housing or even destruction to occur, despite the excess pressure valve, especially for very high pressures, for example, of up to 300 bar. Also, in the opposite case of a significant pressure load from the outside, the prior art does not have housing solutions for high-pressure applications that are sufficiently stable.